To hide the seconds input, use the following:
(function() {
acf.add_filter('date_time_picker_args', function( args, field ){
args.showSecond = false;
return args;
});
})();
There are also options for ‘showHours’, ‘showMinutes’, ‘showMillisec’, ‘showMicrosec’ and ‘showTimezone’.
See the options tab in the documentation
